In the case of absorbent articles such as diapers, sanitary towels, incontinence protection, etc., the application of patterns in the form of texts, images, symbols or the like to certain layers included in the article is previously disclosed. Combinations comprising at least two of the pattern forms are also encountered. The texts and the symbols are preferably of an informative nature, for example in the form of a user instruction, a warning text or product information such as a size indication. The images are preferably in the form of decorative patterns, product information or user instructions. Patterns in the form of trademarks and/or company logotypes are also commonly encountered.
The pattern is usually arranged on one of the layers that forms the outside of the article when it is used, for example on the front or the rear end part of the article, on fastening tabs or on a side panel. It is especially common for the pattern to be arranged on the outside of the article on or close to the waist area of the article.
The pattern sometimes relates to instructions in respect of how the article must be applied to the wearer, the suitable article size for a certain body weight and the like.
Such patterns are commonly positioned together with other types of pattern such as a distinctive product mark, purely decorative patterns, positioning indicators for example for attachment flaps, indicators to show which end of the article must be positioned towards the front on the wearer, and so on.
The articles thus comprise different types of patterns, some intended to inform the user about handling the article, some simply intended to make the article more visually attractive, and some intended to warn of incorrect handling.
Certain patterns, intended to warn of incorrect handling which may be associated with a risk, such as a warning of the risk of suffocation if a child places a baby's diaper over its head, must naturally be capable of being read by a parent before the incorrect handling occurs.
Certain other patterns inform of less serious incorrect handling, such as information to the effect that the size of the article is incorrect in relation to the body size of the wearer, that the attachment flaps have been tightened too tightly around the wearer's waist or the like. This type of information does not need to be made visible until the incorrect use has taken place, in conjunction with which the incorrect use can be corrected directly or on the next occasion that an absorbent article is changed on the wearer, or even on the next occasion on which new absorbent articles are purchased.
Indicators for demonstrating the excessive stretching of a layer of material are described in PCT document WO 96/31175. The document describes a layer of material comprising a pattern consisting of curved lines when the layer of material is not stretched. The curved lines face in the intended direction of stretching. When the layer of material is stretched, the radii of curvature of the lines increase, in conjunction with which the initially curved lines become straighter, in conjunction with which the curvature of the lines gives an indication of by how much the layer of material has been stretched.
One disadvantage associated with the solution in WO 96/31175 is that the curved lines, regardless of whether or not overstretching has occurred, are always visible on the absorbent article. Patterns which are always visible on the absorbent article must naturally exhibit a certain degree of harmony with other patterns on the article, for which reason the warning signal cannot be executed sufficiently clearly and distinctly. A very clear and distinct warning signal runs the risk of dominating the pattern of the article in relation to other patterns that it is wished to emphasize on the article.
Another disadvantage is that the user must understand the symbols in the form of curved lines, and must also understand what it means when the curvature of the initially curved lines is changed and the level of change at which excessively high stretching of the layer of material has been reached.
If the layer of material is elastic, or if the layer of material is attached to an elastic layer of material, a third problem arises because the curvature of the curved lines essentially reverts to the original curvature when stretching of the layer of material ceases. This means that it is not possible to perform a verification in order, for example, to investigate whether the absorbent article has been tightened too tightly around the wearer's waist.